Foam generating apparatus



Sept. 15, 1931. H. BURMEISTER 1,823,559

FOAM GENERATING APPARATUS Filed Nov. 12. 1927 d7 l7 jlj'j, 15 16 3 INVENTOR HANS BURME /5 TE R ATTORNEY Patented Sept. 15, 1931 Eran STATES ii e eNr r HANS BUR-MEISTER, OF IBERLIN GERIHANY. ASSIGN OR TO lY RENE-MINIMAX CORPO- RATION, A' CORPQRA'IIHI9I|. T DELAWARE i roam GENE ATIN APPARATUS Application md November 12',"i927. Serial No. 232,784. i

The present invention relates to apparatus for producing foam for 1'ire' extinguishing purposes and has for an object to provide improved means for combining powder and 5 water to form foam.

Figure 1 is a central sectional view of a generator constructed in accordance with the principles of the invention,

Figure 2 is a cross-sectional detail 'view showing the arrangement of the adjustable spray device, and 1 Figure 3 is a central sectional view of an embodiment having a plurality of ejectors 20 discharging into a mixing chamber.

The apparatus shown in Figs. 1 and 2 for the purposes of illustrating the invention has a suitable hopper 5 for carrying a charge of foam forming powder. The opening 6 in the bottom of the hopper may conveniently be circular. In this opening is positioned a fitting 7 connected to a water inlet 8 and having a nozzle 9 cooperating with a suitable outlet 10 to form an ejector. Above the ejector a catch plate 11 serves to sufficiently close the opening 6 to support the charge of powder when dry in the hopper 5. This plate also serves with the side walls 12 to provide a feeding chamber for the ejector.

under the edge of the opening 6. a distance,

depending upon the angle of repose of the powder to be used, sufiicient to prevent any' substantial quantity of the powder from falling through to the feeding chamber, while dry.

A spray device 15' isarra-nged above the catch plate to direct a conical. sheet of water 1 into the mass of powder above the catch plate to wash it down between the catch plate and the edge of the hopper opening to the feed chamber when the device is in use.

shown, the ejector nozzle 9 and the spray de The outer edge of the catch plate 11 projects justable and, as shown, comprises an'upper conicalmember' 16 which is screw. threaded mto the cooperating member 17 and held'in adjustable position by a setscrew'lS. Ordinarily it is so adjusted that approximately one-sixth of the water supplied to the ap paratuswill pass through thespray device and over the catch plate. The sheet of water is directed downwardly toward and over the I catch plate to wash the powder into the ejecttir feed chamber. A deflector plateli) is supported above the edge of the catch plate and curved downwardly to deflect the'stream of water or water and foam forming mateterial downwardly. the distance between the catch plate and the-deflector being so ad justed as to reduce the churning 'eflect around the edge of the catch plate and in the feed chamber as much as possible. "narily it' is more advantageous to position the deflector plate relatively close to the.

catch plate as shown. Vents 20 lead from "the upper part of the feeding chamber to the atmosphere to prevent, during operation, 'any substantial variation of pressure'in. this portion of the device. i

-" 'The apparatus shown in-Fig. 3 is of the same'general character as that shown in Fig. 1 but embodies a mixing chamber. As shown, the hopper with an opening'26 in the bottom receives the charge of foam forming powder which is supported by a catch plate27.

A plurality of ejectors are formed by the nozzles 28 cooperating with suitable outlets 29 leading into the mixing chamber 30. Each outlet is closed by a flap valve 31 arranged to open to permit'fiow of foam forming materials outwardbut to close in the event the backpressure inthe mixing chamber exceeds the pressure within the ejectors. The foam may be led from the mixingchamber through a suitable outlet 32 as by means ofa hose.

- Ithas been found that an ejector will under the same conditions draw in a liquid very much-more efl'ectively than'it will draw in a dry powder. In the described apparatus and process advantage is taken of this fact by converting the dry powder contained in the hopper-into a relatively freefiowing liquid slurry before subjecting it to the. action. of

the ejector. It is thus possible to feed into the water stream continuously a greater proportionof chemicals than could be supplied to the stream by an ejector operating upon dry powder. Moreover, the rate at which the chemicals are supplied in my apparatus and process dependsupon the regulation of the sheet of spray that isused to wash the powder'over the catch plate. By regulating this spray, it is possible tofeed the chemicals at such rate as may be desired in proportion to the volume of the stream and thusto vary the quality of the foamproduc'ed to suit the hopper for foam forming powderhaving an opening in the bottom thereof. a 'ca-tch plate beneath and close to said opening to sustain the powder therein and means for washing powder over the edge of said catch plate. substantially as and for the purpose described.

2. In apparatus for generating foam for fire extinguishing purposes. in combination. a hopper for foam forming powder having opening in the bottom thereof. an eiector beneath said opening. achiamber ben'eat'h said opening serving as a feed chamber for said eiector, a catch plate beneath saidopening and arranged to support a supplv of drypowder in said hopper. a spray device arran ed to direct a'stream of water over said catch plate to wash powder into said feed chamber. a curved deflector late extendin over the edge of said catch plate and curved downwardly to deflect the water-and material washed therebv downwardly, and a ventleading from the feed chamber, substantially as described. i i

3. In apparatus for generating foam for fire extinguishing purposes. in combination. a hopper for foam forming material having an opening in the bottom thereof. a catch plate beneath said opening. means for directducing powder, said container having a discharge openlng, a member havmg a surface ad aCent said openmg, means for dlrectlng a continuous stream of water to wash the powder from sald container agamst sald surface,

and means for forcing the slurry so formed into a continuously flowing stream of water.

6. In apparatus for generating fire extinguishing foam a container for foam producing powder, a chamber communicating with said container, means for directing a continuous stream of water to Wash the pow "derinto said cli'amberand thereby produce a slurry, means for directly introducing air into said chamber, and means for passing the slurry from said chamber into a, continuously flowing stream of water. Y

HANS BURMEISTER.

ing a stream of water over said'catch' plateto wash the foam formin material throu h said opening-and a deflector plate adiazcent theedge of said catch late for determining the direction of flow of said stream, substantiall v as described. I

4. The process of producing a continuous stream of fire extinguishingfoam' which comprises directingapproximately one sixth of a continuously flowing stream of water against the bottomof a bulk supply of foam produc- 5. In apparatus for generating fire extmgrushmg foam a container for foam proing chemicals to gradually wash the same: I fromsaid supply, and drawing the slurry thus produced into the balance of said stream. 

